Elsevier

Epilepsy & Behavior

Volume 17, Issue 2, February 2010, Pages 178-182
Epilepsy & Behavior

EEG abnormalities and epilepsy in autistic spectrum disorders: Clinical and familial correlates

https://doi.org/10.1016/j.yebeh.2009.11.014Get rights and content

Abstract

Our aim was to examine the characteristics of EEG findings and epilepsy in autistic spectrum disorders (ASD) and the associated clinical and familial risk factors. Fifty-seven children (86% male) with ASD, mean age 82 ± 36.2 months, were included in the study. Thirty-nine (68.4%) children had the diagnosis of autism, 15 (26.3%) had Pervasive Developmental Disorder Not Otherwise Specified, and 3 (5.3%) had high-functioning autism. One hour of sleep and/or awake EEG recordings was obtained for each child. All patients were evaluated with respect to clinical and familial characteristics and with the Childhood Autism Rating Scale, the Autism Behavior Checklist, and the Aberrant Behavior Checklist. The frequency of interictal epileptiform EEG abnormalities (IIEAs) was 24.6% (n = 14), and the frequency of epilepsy was 14.2% (n = 8). IIEAs were associated with a diagnosis of epilepsy (P = 0.0001), Childhood Autism Rating Scale Activity scores (P = 0.047), and a history of asthma and allergy (P = 0.044). Epilepsy was associated with a family history of epilepsy (P = 0.049) and psychiatric problems in the mother during pregnancy (P = 0.0026). Future studies with larger samples will help to clarify the possible associations of epilepsy/IIEAs with asthma/allergy, hyperactivity, and familial factors in ASD.

Introduction

Autistic spectrum disorders (ASD) are devastating conditions with an onset in early childhood and core symptoms of varying degrees involving communication and social and cognitive development, and usually sparing gross motor development. In 1943, Kanner was the first to describe the case of an autistic individual who developed epilepsy [1]. The frequency of epilepsy in autism ranges from 4% to 42% according to different studies [2], [3], [4], [5], [6]. It is known that a significant majority of patients with ASD without seizures have interictal epileptiform EEG abnormalities (IIEAs) on routine EEG studies [5], [6]. The incidence of IIEAs in autistic individuals was found to be between 6% and 74% [5], [6], [7], [8].

Previous studies have reported age, mental status and neurological findings as risk factors for epilepsy in ASD. There is a bimodal age distribution of seizures in autism: one peak occurs before 5 years of age and the other in adolescence after age 10 [7], [9], [10]. Individuals with ASD who have profound mental retardation and/or cerebral palsy are at high risk for epilepsy [5], [7]. However, whether there are other factors associated with epilepsy and epileptiform EEG abnormalities in ASD remains unknown. Indeed, although not previously shown, the factors associated with epilepsy and IIEAs may differ. The aim of this study was to examine the characteristics of EEG findings and epilepsy in ASD subtypes and the association between epilepsy and EEG abnormalities and clinical, psychiatric, developmental, and familial risk factors.

Section snippets

Methods

Fifty-seven patients between the ages of 2 and 18 years who were diagnosed with ASD (autism, Asperger syndrome, Pervasive Developmental Disorder Not Otherwise Specified [PDD-NOS], high-functioning autism [HFA]) according to DSM-IV [11] criteria were included in the study. For all patients, 1-hour recordings of sleep and/or awake EEGs were obtained. Patients with a diagnosis of schizophrenia, schizophrenic disorder or any other psychotic disorder, Rett syndrome, childhood disintegrative disorder,

Results

The mean age of the total sample was 82 ± 36.2 months (range: 30–192 months). The mean age of children with autism was 79 ± 32 months, whereas the mean ages of those with PDD-NOS and HFA were 87 ± 42.7 and 108 ± 44.4 months, respectively. Fifty-nine percent of children with autism were under the age of 6 years, whereas 73% of patients with PDD-NOS were above 6 years of age. Forty-nine patients (86%) were boys and 8 (14%) were girls. Thirty-nine patients (68.4%) were diagnosed with autism, 15 (26.3%) with

Discussion

In this study, children with ASD were evaluated in terms of psychiatric, systemic, and familial characteristics. Most of the previous studies of EEG findings and epilepsy in children with ASD were performed in children with autism, and associations other than age, mental status, and neurological findings were not examined. We question whether the psychiatric, systemic, and familial characteristics of patients with ASD have an influence on the presence of epilepsy and/or IIEAs.

The prevalence of

Conclusion

The frequencies of epilepsy and IIEAs are higher in children with autism compared with the normal population. However, the possible association of epilepsy/IIEAs with factors other than cognitive level and age of patients has not been investigated thoroughly. Clinical medical factors associated with IIEAs such as asthma/allergy and neurobehavioral correlates such as hyperactivity were prominent findings in our study. Studies with larger samples focusing on developmental, psychiatric, medical,

References (36)

  • L. Kanner

    Autistic disturbances of affective contact

    Nerv Child

    (1943)
  • R.F. Tuchman et al.

    Autistic and dysphasic children: II. Epilepsy

    Pediatrics

    (1991)
  • R.F. Tuchman et al.

    Regression in pervasive developmental disorders: seizures and epileptiform electroencephalogram correlates

    Pediatrics

    (1997)
  • V. Wong

    Epilepsy in children with autistic spectrum disorder

    J Child Neurol

    (1993)
  • H.L. Kim et al.

    Absence of seizures despite high prevalence of epileptiform EEG abnormalities in children with autism monitored in a tertiary care center

    Epilepsia

    (2006)
  • I. Olsson et al.

    Epilepsy in autism and autistic-like conditions

    Arch Neurol

    (1988)
  • American Psychiatric Association Task Force on DSM-IV. Diagnostic and statistical manual of mental disorders: DSM-IV....
  • T. Yilmaz-Irmak et al.

    Otizm davraniş kontrol listesinin geçerlik ve güvenilirliğinin incelenmesi

    Çocuk ve Gençlik Ruh Sağliğı Dergisi

    (2007)
  • Cited by (45)

    • Ictal EEG in patients with autistic spectrum disorder and epilepsy

      2020, Epilepsy Research
      Citation Excerpt :

      We found no specific seizure type or epilepsy syndrome to be associated with ASD in our population. This is similar to earlier studies that found diverse seizure types and interictal EEG abnormalities in ASD populations (Ekinci et al., 2010). Interictal EEG abnormalities often occur in ASD patients without epilepsy and may contribute to cognitive or behavioral disorders (Luz-Escamilla and Morales-Gonzalez, 2019; Gelinas et al., 2016).

    • Mouse Behavior and Models for Autism Spectrum Disorders

      2016, Neuronal and Synaptic Dysfunction in Autism Spectrum Disorder and Intellectual Disability
    • Clinical characteristics of children and young adults with co-occurring autism spectrum disorder and epilepsy

      2015, Epilepsy and Behavior
      Citation Excerpt :

      Similarly, a longitudinal study looking into the incidence of epilepsy in ASD reported that the presence of epilepsy was independently associated with a broader autism phenotype in relatives (i.e., subthreshold autistic traits) [21]. Studies also show that a family history of epilepsy is associated with an increased risk of epilepsy in those with ASD [4,20,29] which is not surprising given the heritability of some of the epilepsy syndromes; however, at least one study did not find this to be true [21]. A few papers have considered other risk factors or associations for the occurrence of epilepsy in ASD, including pre- and perinatal issues, developmental problems, and family histories (e.g., presence of psychiatric and neurological disease), but most of the studies had samples that were too small to draw reliable conclusions.

    View all citing articles on Scopus
    View full text